Airworthiness Directive · Amendment 39-17675 · Power plant
The Boeing Company Airplanes
This AD applies to The Boeing Company airplanes, certificated in any category, identified in paragraphs (c)(1) and (c)(2) of this AD.
(1) Model 747-8 and 747-8F series airplanes powered by GEnx-2B67 or GEnx-2B67B engines.
(2) Model 787-8 airplanes powered by GEnx-1B64, GEnx-1B67, GEnx-1B70, GEnx-1B64/P1, GEnx-1B67/P1, GEnx-1B70/P1, or GEnx-1B70/75/P1 engines.
Note 1 to paragraph (c)(2) of this AD: The engine nameplate may also include a suffix such as “G03,” which is the applicable Bill of Materials (See FAA Type Certification Data Sheet T00021SE basic model identifier).
We are adopting a new airworthiness directive (AD) for The Boeing Company Model 747-8 and 747-8F series airplanes and Model 787-8 airplanes powered by GEnx engines. This AD requires revising the airplane flight manual to advise the flight crew of potential ice crystal icing (ICI) conditions at high altitudes, and to prohibit operation in moderate and severe ICI conditions. This AD also requires inspecting the engine after any ICI event is detected by the flight crew. This AD was prompted by reports of engine damage and thrust loss events as a result of flying in high altitude ICI conditions. We are issuing this AD to ensure that the flight crews have operating instructions to avoid flight into ICI conditions that can lead to engine damage and thrust loss events; unrecoverable thrust loss on multiple engines can lead to a forced landing.
Within 7 days after the effective date of this AD, revise the Certificate Limitations chapter of the applicable Boeing AFM to include the statement provided in figure 1 to paragraph (g) of this AD. This may be done by inserting a copy of this AD into the AFM.
In order to prevent loss of thrust and engine damage due to ice crystal icing, for operations at or above 30,000 feet, when approaching, or in, instrument meteorological conditions or visible moisture:
The flight crew must comply with the Avoidance of Ice Crystal Icing procedure contained in the Operating Procedures chapter of this manual.
When following the Avoidance of Ice Crystal Icing procedure, flight is prohibited within 50NM of amber or red radar returns that are displayed below the airplane's flight path.
Note 2 to figure 1 to paragraph (g), figure 2 to paragraph (h), and figure 3 to paragraph (i) of this AD: When statements identical to those in figures 1, 2, and 3 to paragraphs (g), (h), and (i) of this AD, respectively, have been included in the applicable chapters of the general revisions of the applicable AFM, the general revisions may be inserted into the AFM, and the copy of this AD may be removed from the AFM.
For Model 747-8 (Intercontinental) and 747-8F (Freighter) series airplanes: Within 7 days after the effective date of this AD, revise the Operating Procedures chapter of the Boeing 747-8 AFM to include the statement provided in figure 2 to paragraph (h) of this AD. This may be done by inserting a copy of this AD into the AFM.
This procedure is required by the AVOIDANCE OF ICE CRYSTAL ICING limitation contained in the Certificate Limitations chapter of this manual. The language below shall not be modified.
Operations in ice crystal icing can cause unrecoverable loss of thrust and engine damage due to ice crystal icing.
For operations at or above 30,000 feet, when approaching, or in, instrument meteorological conditions or visible moisture:
Operate weather radar in automatic mode and gain knob set to the 12 o'clock position, or if in manual mode adjust gain to maximum and set tilt between −1 and −3.
If areas of green, amber or red weather radar returns are observed along the flight path:
Use manual weather radar tilt control mode and vary the tilt between −3 and −5 degrees and set the gain knob to the 12 o'clock position to determine if amber or red returns are present below the airplane's flight path.
Flight is prohibited within 50NM of amber or red radar returns that are displayed below the airplane's flight path.
For Model 787-8 airplanes: Within 7 days after the effective date of this AD, revise the Operating Procedures chapter of the Boeing 787 AFM to include the statement provided in figure 3 to paragraph (i) of this AD. This may be done by inserting a copy of this AD into the AFM.
This procedure is required by the AVOIDANCE OF ICE CRYSTAL ICING limitation contained in the Certificate Limitations chapter of this manual. The language below shall not be modified.
Operations in ice crystal icing can cause unrecoverable loss of thrust and engine damage due to ice crystal icing.
For operations at or above 30,000 feet, when approaching, or in, instrument meteorological conditions or visible moisture:
Operate weather radar in automatic mode and 0 manual gain adjustment, or if in manual mode adjust gain to maximum and set tilt between −1 and −3.
If areas of green, amber or red weather radar returns are observed along the flight path:
Use manual weather radar tilt control mode and vary the tilt between −3 and −5 degrees and select 0 manual gain adjustment to determine if amber or red returns are present below the airplane's flight path.
Flight is prohibited within 50NM of amber or red radar returns that are displayed below the airplane's flight path.
After any flight crew report of the appearance of an engine indicating and crew alerting system (EICAS) message that displays “ENG THRUST (L,R)” (for Model 787-8 airplanes) or “ENG (1, 2, 3, or 4) THRUST” (for Model 747-8 and 747-8F airplanes) during operation at or above 30,000 feet pressure altitude: Do borescope inspections of the first stage blade of the high pressure compressor of the engines to detect damage, as specified in paragraph (j)(1) or (j)(2) of this AD, as applicable. Correct any damage before further flight.
(1) For Model 747-8 and 747-8F series airplanes: Before further flight, inspect each engine for which an EICAS ENGINE THRUST message was displayed. A minimum total of 3 engines must be inspected before further flight. Within 5 flight cycles after the EICAS message was displayed, inspect the fourth engine, unless already accomplished as specified in this paragraph.
(2) For Model 787-8 airplanes: Before further flight, inspect both engines.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
